Presently, sanding devices of practically all types effect sanding on flat surface, such as by a sanding disc or belt. An outstanding disadvantage of such devices is that in many applications, particularly those for sanding rounded or even cylindrical surfaces, it is not possible to do so effectively with common types of sanders since they do not readily conform to curved surfaces sought by the workman. Moreover, it is difficult or even impossible with presently known sanders to sand the entire surface of a pipe that is mounted closely adjacent a wall because of the small space therebetween. Also, present sanders are not readily convertible from a portable type to one that is rigidly mounted on the workbench.
Partially rounded workpieces typified by the necks of musical instruments may be fastened face-to-face in order to prevent imbalance while rough shaping their back side in a wood lathe. But finishing cannot be done on a lathe because (1) colorfully grained woods used in musical instruments have irregular grain which tends to tear laterally against the lifting action of a lathe tool; (2) the final shape is almost never a "segment of a circle".
Instrument necks can also be shaped using high-speed routing machines. These machines are too expensive for entrepreneur instrument builders. Hand-made necks are often shaped with planes, draw knives and hand-held sanding blocks which are either slow or dangerous.
Tanks and other round vessels including piping used in industry, often are sand-blasted in preparation for re-coating. The equipment used in the sand-blasting operation is expensive due to the need for parts to withstand the abrasive action of the sand. And most of the sand used in the process cannot be re-claimed due to contamination. And the process is dangerous to the worker and to the environment.
There currently is no tool available to economically and safely work the surface of round/elliptical shapes.